对话式教学在教育研究领域受到越来越多的关注，并被提倡为提高课堂教与学质量、发展学生思维品质的方式。然而,在课堂实践层面，尤其是在英语课堂，对话式教学的应用仍然比较模糊，亟待深入研究。本研究旨在探究教学改进项目中高中英语课堂教学向对话式教学的转变以及促成这些转变的因素，从而加深对对话式教学的理解，并为教师开展具有对话性的课堂教学提供建议。 本研究采用多案例研究方法。三名教师参与其中并构成三个案例。本研究收集并转写了每名教师在教学改进过程中的三节90分钟的课，以进行深入分析。研究者辨别出包含对话式教学指标的课堂片段，并进行深度剖析，以挖掘在每个案例中，课堂教学是如何向对话式教学转变的。此外，本论文还开展了跨案例研究以找出转变在三个案例中具有哪些相同点和不同点。三名教师在每次课后分别参与了反思性访谈，通过刺激性回想的方式对与转变有关的课堂片段加以解释说明。 研究发现，三个案例均体现了不同程度的向对话式教学的转变，并导致了对话式教学雏形的出现。然而每个案例中的转变遵循不同的模式，并体现在不同指标的变化上。此外，本研究亦指出了促进转变发生的五个因素，即和学生的个人经历建立关联、创设情景、探究意义、发展学生的思维品质、关注学生的“学”和建立平等的师生关系。总之，本案例研究描绘了对话式教学在高中英语课堂中所逐渐呈现出的动态、复杂且富有生机活力的景象，并为提高英语课堂教学质量、促进职前和在职外语教师教育提供启示。

Dialogic teaching (DT) has received increasing attention in the field of educational research. It has been advocated as a means to improve the quality of classroom teaching and learning, as well as to develop students’ thinking capacity. However, the practical landscape of DT, especially in English classrooms, remains rather vague and calls for in-depth research. The purpose of the present study is to examine the transition to DT in senior high English classrooms during a teaching improvement project and to explore the factors contributing to the transition, so as to develop a better understanding of it and to provide suggestions for teachers to teach in a dialogic way. The study adopts a multiple-case approach. Three teachers participated and constituted the three cases. The three 90-minute lessons of each teacher during the project were collected and transcribed for thorough analysis. Episodes of lessons involving the indicators of DT were identified and dissected in order to delve into how the transition to DT is embodied in each case. Besides, a cross-case analysis was also conducted so as to figure out how the transition is similar and different among the three cases. The three teachers also participated in reflective interviews after each lesson, in which they provided explanations for the episodes pertinent to the transition via stimulated recall. The findings showed that there were different degrees of transition to DT in the three cases, which led to embryonic forms of dialogic teaching. But the transition in each case followed a different pattern and was embodied by the changes in different indicators. Besides, five factors contributing to the transition were also pointed out, namely, relating to students’ personal experience, creating contexts and probing into meaning, developing students’ thinking capacity, focusing on students’ learning and building an egalitarian teacher-student relationship. In general, this multiple-case study delineated an emerging, dynamic, complex and vigorous landscape of dialogic teaching in senior high English classrooms, which provided implications for improving the quality of English classroom teaching and promoting the pre- and in-service English teacher education.